Control apparatus for internalcombustion engines



Aug. 8, 1950 CONTROL APPARATUS FOR INTERNAL-COMBUSTION ENGINES 1 w h S W a h S 5 v New 3 N P on w v 8Ez8 \I 555i h b 8 F U m 0m 0 w 1 a F. 6 x w mm D vm d e l 1 F INVENTOR.

AGENT 3, 1950 L. LEE, 11 2,517,688

CONTROL APPARATUS FOR INTERNAL-COMBUSTION ENGIQES Filed Dec. 6, 1945 5 Sheets-Sheet 2 I INVENTOR. lE/EHTU/V 55] AGENT Aug. 8, 1950 L LEE, 1. 2,517,688

CONTROL APPARATUS FOR INTERNAL-COMBUSTION ENGINES Filed Dec. 6, 1945 5 Sheets-Sheet 3 mmvron. g Z E/EH 72m 155 l? AGENT FiG.3

Aug. 8, 1950 1| 2,517,638 I CONTROL APPARATUS FORINTERN AL-COMBUSTION ENGINES Filed Dec. 6, 1945 5 Sheets-Sheet 4 FIG. 4

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INVENTOR.

Z 5/5/7 ra/v 5 I BY AGENT Aug. 8, 1950 CONTROL APPARATUS FOR INTERNAL-COIBUSTION ENGINES Filed Dec. 6, 1945 Fl G. 6

L. LEE, ll

5 Sheets-Sheet 5 III/ l NVENTOR. 15/5/1727 1 5 I AGENT Patented Aug. 8, 1950 UNITED STATES PATENT OFFICE CONTROL APPARATUS FOR INTERNAL- COMBUSTION ENGINES of New Jersey Application December 6, 1945, Serial No. 633,169

28 Claims. (Cl. 123-171) gine is commonly regulated so as to control the engine temperature. Since an engine runs cooler on a rich mixture of fuel and air than on a lean mixture, it has been proposed to enrich the mixture at high power outputs so as to limit the rise in temperature of the engine. It is also possible to limit the engine temperature rise by positively limiting the maximum power output. Ignition timing also has an effect on engine temperature, and it may be varied in accordance with the operating conditions of the engine for the purpose of regulating the engine temperature.

It is an object of the present invention to provide control apparatus for an internal combustion engine which coordinates all the various conditions and devices which may affect engine temperature to maintain an optimum engine temperature and maximum thermal eflicienoy.

Another object of the present invention is to provide, foran air-cooled engine, an arrangement wherein the cowl flaps which control the passage of cooling air past the engine and the fuel-air ratio regulating apparatus are coordinated.

A further object is to provide such an arrangement wherein the cowl flaps and the fuelair ratio are coordinated in response to:

(1) Engine temperature (2) Rate of cooling air flow (3) Rate of combustion air flow Another object is to provide an arrangement of the type described wherein the ignition timing is coordinated with the other control elements anism for varying the fuel-air ratio in a carburetor for an internal combustion engine.

A further object is to provide means for controlling various factors affecting engine temperature in response to conditions which indicate future changes in engine temperature, so as to anticipate such changes and maintain said temperature relatively constant.

A further object is to provide apparatus for controlling the flow'of cooling air over an aircooled engine in response to a condition indicative of the power output of said engine.

A further object is to regulate the cowl flaps which control the flow of cooling air over an aircraft engine so as to minimize the drag produced bythe flaps and tending to slow the aircraft.

A further object is to control various factors aflecting the operation of an internal combustion engine so as to operate said engine substantially without detonation.

Other objects and advantages of the present invention will become apparent from a consideration of the appended specification, claims and drawings, in which:

Figure 1 is a more or less diagrammatic view. partly in section, of an aircraft engine including control apparatus built in accordance with the present invention,

Figure 2 is a cross-sectional view of a motor controlling switch mechanism such as that illustrated schematically in Figure 1,

Figure 3 is a diagrammatic illustration of a carburetor such as that shown schematically in Figure 1, illustrating the important structural details of the carburetor,

Figures 4 and 5 show different positions of the mixture control mechanism of the carburetor of Figure 3, and

Figure 6 shows a detonation responsive device adapted for use in the apparatus of Figure 1.

Referring to Figure 1, there is shown an aircraft engine nacelle ill. in which is mounted an engine including a plurality of cylinders I2 and a crankcase ll. The engine is disposed in driving relationship with the propeller IS. The engine is of the well-known radial air-cooled type. Air enters the nacelle at the front, just in back of the propeller and is directed by means of a baflle plate l8 thru passages between cooling fins 20 on the cylinders l2. After flowing past,

the cooling fins, the air passes backwardly thru ings controlled by cowl flaps 22.

The bai'ile plate I8 and the cooling fins 28 form a fixed restriction in the path of the cooling air. Since the pressure drop across afixed restriction in a fluid conduit is a measure of the rate of flow of fluid thru it, the pressure drop across this restriction, may be used as a measure of the rate of fiow of cooling air past the engine.

Air for combustion purposes enters a scoop 24 and passes thru a carburetor 28, and then into the engine. The rate of flow of combustion air thru the carburetor may be controlled by a pair 44 and a link 48 which connects the rod to a rotatable frame 48. I

An ignition timing control device is schematically indicated at 58. This device is operated thru links 52, 84 which also connect to the frame 48.

,' The cowl fiaps 22 are also connected by means of links such as those shown at 58 and 88 to frame 48.

. The frame 48 is rotated by an electric motor generally indicated at 88. The motor 88 is reversible and is controlled by a switch mechanism generally indicated at 82. The details of the switch mechanism 82 are shown in Figure 2. As there shown, the switch mechanism 82 includes a housing separated into three sections, 84, 88 and 88. The sections 84 and 88 are recessed to provide between them a chamber which is divided by a flexible diaphragm I8 into two expansible chambers 12 and 14. The housing sections 88 and 88 are similarly recessed to provide between them a chamber which is divided by a flexible diaphragm I8 into expansible chambers I8 and 88. A chamber 82 is formed in the housing section 88. A rod 84 is attached to the diaphragms I8 and I8 and extends slidably thru the walls of the housing sections and into the chamber 82. At its lower end, the rod 84 carries an arm 88 provided at its extremity with oppositely disposed contacts 88 and 88. The rod 84 is connected to ground as indicated at 82. A tension spring 84 is attached to the lower end of rod 84 and extends to one end of a lever 88. The other end of lever 88 is connected thru a joint 88 to a switch operating rod I88. The joint 98 and rod I88 are positioned by an expansible bellows I82. The rod I88 carries a pair of spaced contacts I84 and I88, which lie on either side of the arm 88 carrying contacts 88 and 88. Contact I 84 is connected to a conductor I88 and the contact I88 is connected to a conductor I I8.

The chambers 12 and I4 are connected respectively thru conduits H2 and H4 to a pair of chambers H8 and H8 (see Figure 3) in the carburetor 28 where a pressure differential is mainward direction, a pressure differential which is a measure of the rate of flow of cooling air over the engine.

A bulb I24 is mounted on one of the engine cylinders and is connected thru a conduit I28 to the bellows I82. The bulb I24 is filled with a suitable temperature responsive fiuid, such as one having a high vapor pressure, so that the bellows I82 expands and contracts with variations in the engine temperature. An increase in the engine temperature causes the bellows I82 to expand, thereby causing engagement of contacts 88 and I88. A decrease in engine temperature causes bellows I82 to contract, thereby moving contact I84 downwardly and tending to engage it with contact 88. At the same time the motion of the free end of bellows I82 is transmitted thru lever 88 and spring 84 to the rod 84, where it tends to move the contacts 88 and 88 to cause engagement of those contacts with the contacts I84 and I88, respectively, sooner than would otherwise be the case. By virtue of the connection of bellows I82 thru lever 88 to rod 84, the travel of the bellows required to produce a given change in the cowl baiile drop is substantially reduced below the travel which would be required if the bellows only positioned contacts I84 and I88.

It may also be observed that an increase in combustion air flowing to the engine, which indicates that the engine temperature will increase, moves the rod 84 downwardly to cause engagement of contacts 88 and I88. An increase in cooling air fiow over the engine, which anticipates a decrease in engine temperature causes the rod 84 to move upwardly, thereby engaging,

. contact 88. Likewise, whenever the combusfion air fiow or the cooling air fiow changes in a direction which anticipates an increase in temperature, the same two contacts are moved toward engagement. On the other hand, when the engine temperature decreases, or when the combustion air flow or cooling air flow changes in a. direction to anticipate a decrease in the engine temperature, contacts 88 and I84 are moved into engagement.

Engagement of contacts 88 and I88 closes an electrical circuit which may be traced (see Figure 1) from the lower terminal of a battery I88 thru a conductor I82, motor 88, conductor III, contact I 88, contact 88, and ground connections 82 and I34 to the upper terminal of battery I 88. This circuit energizes motor 88 for rotation in a direction to drive the frame 48 counter-clockwise about its pivot 48 so as to open the cowl flaps.

Engagement of contacts 88 and I 84 completes a circuit which may be traced from the lower terminal of battery I38 thru conductor I32, motor 88, conductor I88, contact I84, contact 88,

and ground connections 82 and I 84 to the upper space in front of the baflle plate I8. ,There is thereby applied to the diaphragm 18, in an upterminal of battery I38. This circuit energizes motor .88 for rotation in a direction to drive the frame 48 clockwise, thereby closing the cowl flaps 22.

When the frame 48 is driven clockwise, then the mixture control is operated to lean the mixture and the ignition timing control is operated to advance the timing. At the same time, frame 48 moves out of the path of stop I28, thereby allowing the throttle to move to a wider open position.

When the frame 48 moves in counter-clockwise direction, the cowl flaps are opened, the mixture is enriched, the ignition is retarded and the opening movement of the throttle is increasingly limited. 1

When the frame 48 turns clockwise, the cooling air flow, the mixture ratio and the ignition timing are all varied in a direction to increase the engine temperature. When it rotates counter-clockwise, those conditions are varied in a sense to decrease the engine temperature. The throttle limit stop is moved at the same time to permit a greater throttle opening and hence greater power output when the engine temperature is low and to reduce the power output when the engine temperature is high.

An engine runs more efliciently when the mixis a measure of the velocity of the air flowing thru ture is lean (within reasonable limits) than when I the mixture is rich. An engine can be run onla leaner mixture when the ignition is advanced than when it is retarded. Both the leaner mixture and the advancing of the ignition tend to make the engine run hotter, The present control system is arranged to allow the engine to run as economically as possible consistent with safe operating temperatures. If the selected operating temperature is exceeded, the system operates the cow] flaps to increase the coo1ing,and at the same time enriches the mixture and retards the ignition timing to decrease the heat output of the engine. If the engine temperature falls below that selected by adjustment of the system, then the system acts to lean the mixture and advance the timing so as to take advantage of the greater economy permitted by the lower temperature.

If the flaps come near their full open position and the temperature continues to increase, the throttle stop comes into play to limit the power output (and hence the heat output) of the engine.

By positioning the cowl-flaps in response to the rate of flow of combustion air to the engine and the rate of flow cooling air to the engine, I have provided a system which maintains the flaps as nearly closed as possible for any given condition of engine power output, since combustion air flow may be used as a measure of power 5 output. Therefore, the drag due to the cowl flaps start, thereby obtaining a more even temperature.

Figure 3 There is shown in detail in Figure 3 a carburetor which may be that shown schematically at 26 in Figure 1.. This carburetor has a mixture control 36 which may be the same as that shown schematically in Figure 1.

There is shown an air induction passage I50, thru which the air flows from an entrance I52, past a venturi I54, throttle blades 28, and a fuel discharge nozzle I56 to an outlet I58. The venturi I54 sets up an air pressure differential which the air induction passage.

A portion of the air flows thru a secondary air passage, The entrance of this secondary air passage is at a plurality of impact tubes I160 whose open end project into the air entrance I52 in a direction to receive the impact of the entering air. From th impact tubes I60, the air flows thru a conduit I62 into a chamber II6 which is located in a fuel meter I64. From the chamber II6, the air flows thru a restriction I66 into chamber II8, which is also located in the fuel meter I64. The air then flows from chamber II8 thru a conduit I68, past a valve I10 into a chamber I12. Chamber I12 is connected thru a passage I14 to the throat of venturi I54. The valve I10 is operated by a bellows I16 mounted in the chamber I12.

The bellows I16 serves to modify the pressure drop across restriction I66 in accordance with varying density of the air flowing thru the air induction passage I50. In this way the pressure drop across restriction I66 may be made to vary in accordance with the mass of air flowing per unit time thru the air induction passage, rather than in accordance with the velocity 01. flow. This efl'ect is described in detail in the co-pending application of Milton E. Chandler, Serial No. 490,281, filed June 10, 1943, now Patent No. 2,393,144, issued January 15, 1946.

Fuel enters the carburewr from a pump (not shown) and flows thru a conduit I18, a fuel regulator I80, a conduit I82, the mixture control unit 36, a conduit I84, an idle valve mechanism I86, a conduit I88, a pressure regulator I90 and a conduit I92 to the fuel nozzle I56.

The fuel regulator I80 includes a diaphragm I94 separating a pair of expansible chambers I96 and I98. A valve 200 is attached to the center of diaphragm I94. Chambers I96 and. I98 are inter-connected thru a restriction 202. The valve '200 is balanced against the pressure in the inlet conduit m. The outlet conduit I82 is connected to chamber I98. Chamber I96is connected thru a conduit 204 to a, chamber 206 in the fuel meter I64. Diaphragm 208 separates chamber 206 from chamber I I8,

The fuel meter I64 also includes a fourth chamber 2I0 separated from chamber II 6 by 9. diaphragm 2 I2. The chamber 2I0 is connected thru a conduit 2I4 to the fuel conduit I88. A diaphragm 2I6 separates the two chambers: H6 and I|8. The diaphragms 2I2, 2I6 and 208areattached at their centers to a pilot valve 2 I0, which controls the flow of fuel from chamber 206 to an outlet conduit 220 which delivers the fuel flowing therethru into the main air induction conduit. A spring 2I I biases the valve 2I8 toward closed position.

The fuel regulator I operates the valve 200 to maintain a pressure in chamber I98 which varies with the pressure in chamber I96. If the pressure in chamber I96 increases, the valve 200 is moved downwardly, thereby permitting additional fuel to flow into chamber I98 until the increase in pressure therein balances the increased pressure in chamber I90. The pressure in chamber I96 may therefore be said to be a measure of the pressure in chamber I98, which is the pressure in the main fuel conduit on the upstream side of the mixture control 36. This pressure is transmitted into chamber 206 in the fuel meter I64 where it acts upwardly on the valve 2I8. The pressure in conduit I88 on the downstream side of the mixture control 36 is transmitted thru conduit 2 I4 to the chamber 2 I8. The difference in pressure between chambers 286 and H8 is therefore a measure of the fuel pressure drop across the mixture control 36. It may be seen that the valve 2I8 is positioned in accordance with the balance or unbalance between two differential pressures, one of which is a measure of the mass of air flowing to the engine per unit time and the other of which is a measure of the rate of fuel flow to the engine, The position of valve 2 I 8 in turn controls the pressure in chamber I86. Therefore the fuel meter I64 and the fuel regulator I88 control the fuel pressure on the upstream side of the mixture control unit 36 in proportion to the mass .of air flowing to the engine.

The pressure regulator I88 acts to maintain a substantially constant pressure on the downstream side of the mixture control 36. The-pressure regulator I98 includes a diaphragm 264 separating a pair of chambers 266 and 268. Chamher 266 receives fuel from the conduit I68. Chamber 268 is vented thru a conduit 218 to conduit I62 and the air entrance I52. A spring 212 biases a valve 214 attached to the center of diaphragm 264 toward closed position, The valve 214 may be balanced against outlet pressure, if-desired. In any event, it operates to maintain a substantially constant pressure in the chamber 266, which pressure is determined by the strength of spring 212.

Since the pressure on the downstream side of the mixture control unit is maintained constant, and the pressure on the upstream side is varied in accordance with the rate of air flow, it may be seen that the pressure differential across the mixture control unit varies in accordance with the rate of air flow. Therefore, a substantially constant fuel-air ratio is maintained.

The ratio of fuel to air may be varied by varying the effective metering area of the flow paths thru the mixture control system. This may be don either by manipulating the manual mixture control link 38 or thru the action of the automatic mixture control rod 44.

' The mixture control 36 includes a casing 222 having formed therein an inlet chamber 224 connected to the conduit I 82, The manual mixture control link 38 rotates a shaft 226, which carries an arm 228 within the chamber 224. The end of arm 228 carries a pin 238 which rides in a slot 232 formed transversely on a valve 234. The valve 234 has a tapered valve portion 236, and an elongated valve portion 238. The tapered valve portion 236 cooperates with a seat 248 to control the flow of fuel out of the chamber 224. The

- elongated valve portion 238 extends thru the seat 248 and moves in a passage 242. The elongated portion 238 is fluted as at 258 to permit the flow of fuel thru the seat 248 whenever the tapered portion 236 is away from the seat. When the valve 234 is in the position shown in Figure 3, fuel can flow thru the mixture control only from chamber 224 thru the flute 258, and thence thru a restriction 252 to the conduit I84, Fuel may also flow thru the flute 258 and thru a valve 254 biased to closed position by a spring 245, and then thru a restriction 258 to the conduit I64. The valve 254 is subject to the fuel pressure differential across the'jet system and opens at high fuel flows to enrich the fuel-air mixture. The position of the valve 234 shown in Figure 3 is known as the lean position of the mixture control.

The manual mixture control link 38 ma be moved to the position shown in Figure 4. which is known as the rich" position. Referring to Figure 4, it will be seen that all the fuel passages which were open in Figure 3 are open and that the fuel may also flow from the flute 258, thru passage 242, a restriction 268 and the restriction 258 to the conduit I34. By the movement of the valve 234, the restriction 268 has in effect been placed in parallel with the restriction 262. The fuel-air ratio is increased since the total metering area of the restrictions in the mixture control has been increased, thereby increasing the rate of fuel flow for a given fuel pressure differential across the mixture control system,

In Figure 5, the valve 234 has been moved to an intermediate position known as the automatic" position. In this position of the manual control link 38, the effective metering area of the mixture control is determined by the position of the automatic mixture control rod 44. The fuel passages thru restriction 252 and thru valve 254 are open as they are in Figure 3. Fuel may also now pass thru restriction 268, but only by flrst passing thru a by-pass conduit 262 whose effective area is controlled b the position of the mixture control rod 44. The fuelair ratio obtained under these conditions is somewhere between that which would be obtained by the control in its lean position and that which would be obtained by the control in its rich position.

Under low air flow conditions, such as those encountered when the engine is idling, the venturi I54 is not accurate as a device for measuring the air flow. Under those conditions it is desirable to have the fuel flow determined in accordance with the throttle position, rather than in accordance with the measurement of the venturi, For this purpose, there is provided the idle valve mechanism I86. This mechanism includes a valve 216, which is operated by a lever 213 connected by a link 288 to the throttle operating link 32. As the throttl moves toward closed position the valve 216 is moved to restrict the conduit I84. The valve 216 then becomes the dominant restriction in the fuel conduit since its effective metering area is then smaller than that of restriction 252. It will be observed that the pilot valve 2" is biased toward closed position by a spring 2 and that valve 288 is biased open by a spring 28I. Both of these springs act in a sense to increase the flow thru the main fuel conduit. When the pressure differential set up by the air venturi is small, as under idle conditions, these two springs determine the pressure differential across the mixture control 36 and the idle valve 216 in series. The idle valve 216 determines the effective metering area at such times. The fuel flow is therefore determined by the throttle position and by the characteristics of springs 28I and 2 under idle conditions.

Figure 6 There is shown in Figure 6 an arrangement for additionally controlling the system of Figure 1 in response to detonation of the engine. Referring to Figure 6, the reference character I24 represents the temperature bulb indicated by the same character in Figure 1. The conduit I26 is connected to it as in Figure 1. A heater coil 388 surrounds a portion of the bulb. This heater coil is connected in an electrical circuit including a battery 382 and a switch 384, operated by a relay 386. The energization of relay 388 is controlled by an amplifier 388; to the input terminals of the amplifier 308 is connected a detonation responsive pickup unit 3"]. This pickup unit may be, for example, the same as that shown in the patent to Draper et al., No. 2,275,675. Upon detonation of the engine, this arrangement responds to energize the relay 306, thereby closing the circuit thru the heater coil 300. This causes the fluid in the bulb I24 to expand giving an indication of higher engine temperature than actually exists. The system of Figure 1 responds therefore to detonation in the same way that it responds to an increase in engine temperature. The cowl flap opening is increased, the fuel-toair ratio is increased, and the ignition timing is retarded. All thesefactors tend to reduce the engine temperature and thereby to reduce any tendency of the engine to detonate.

While I have shown this control system as applied to an air-cooled engine, it should be readily apparent that it could be applied with equal facility, to a liquid cooled engine. The pressure drop which measures the cooling air fiow could then be taken on the opposite sides of the radiator by which the heat in the cooling fluid is transferred to the air. Alternatively, a restriction in the coolant line could be used to establish a pressure drop which measures the coolant flow.

sponse to adecrease in the flow of cooling air past said engine and to close said flaps and. lean the mixture in response to an increase in the flow of cooling air past said engine.

5. Control apparatus for an internal combustion engine, comprising cowl flaps for regulating the flow of cooling air over said engine, mixture control means for regulating the ratio of fuel to air supplied to said engine, control means responsive to the rate of combustion airflow to said engine, and means including said control means for simultaneously controlling the position of said cowl flaps and said mixture control means to open said cowl flaps and enrich the mixture in response to an increase in the rate of flow of combustion air to said engine and to close said flaps and lean the mixture in response to a decrease in the rate of flow of combustion air to While I have shown and described a preferred embodiment of my invention, other modifications thereof will readily occur to those skilled in the art, and I therefore intend my invention to b limited only by the appended claims.

I claim as my invention:

1. Control apparatus for an internal combustion engine, comprising means for cooling said engine, means for regulating the effectiveness of said cooling means, mixture control means for regulating the ratio of fuel to air supplied to said engine, first control means responsive to the temperature of said engine, second control means responsive to the rate of flow of cooling air past said engine, third control means responsive to the rate of combustion air flow to said engine, and means including said first, second and third control means for simultaneously controlling both said regulating means.

2. Control apparatus for an internal combustion engine, comprising means external of said engine for cooling said engine, means for regulating the effectiveness of said cooling means, mixture control means for regulating the ratio of fue1 to air supplied to said engine, and means for simultaneously controlling both said regulating means so as to enrich the mixture as the effectiveness of the cooling means is increased and to lean the mixture as, the effectiveness of thecooling means is decreased.

3. Control apparatus for an internal combustion engine, comprising cowl flaps for regulating the flow of cooling air over said engine, mixture control means for regulating the ratio of fuel to air supplied to said engine, control means responsive to the temperature of said engine, and means including said control means for simultaneously controlling the position of said cowl flaps and said mixture control means to open saidfi-aps and enrich the mixture in response to an increase in engine temperature and to close the flapsand lean the mixture in response to a decrease in engine temperature.

4. Contro1 apparatus for an intern-a1 combustion engine, comprising cowl flaps for regulating the flow of cooling air over said engine, mixture control means for regulating the ratio of fuel to air supplied to said engine, control means responsaid engine.

6. Control apparatus for an internal combustion engine, comprising cowl flaps for regulating the flow of cooling air over said engine, mixture control means for regulating the ratio of fuel to air supplied to said engine, means for controlling the ignition timing of said engine, and meansfor simultaneously controlling said cowl flaps, and said ignition timing control means to simultaneously open said flaps, enrich said mixture and retard said ignition timing or to simultaneously close said flaps, lean said mixture and advance said ignition timing.

7. Control apparatus for an internal combustion engine, comprising cowl flaps for regulating the flow of cooling air over said engine, mixture control means for regulating the ratio of fuel to air supplied to said engine, a throttle for controlling the flow of combustion air to said engine, stop means .for limiting the opening movement of said throttle, and means for simultaneously controlling said cowl flaps, said mixture control means, and said stop means to simultaneously open said flaps, enrich said mixture and increasingly limit the opening movement of said throttle or to simultaneously close said flaps, lean said mixture .air past said engine, third control means responsive to the rate of combustion air flow to said engine, and means including said first, second and third control means for simultaneously controlling said cowl flaps, said mixture control means, said ignition timing control means and said throttie stop means to simultaneously open saidflaps,

enrich said mixture, retard said ignition and inof the rate of flow of, combustion air thru said conduit, reversible electrical motor means for operating said regulating means, double-throw switch means for controlling said reversible motor means, said switch means comprising two pairs of relatively movable contacts, means for positioning one of said pairs of contacts including two pairs of expansible chambers, a pair of flexible diaphragms, each diaphragm separating one I of said pairs of chambers, means for transmitting the pressures on the opposite sides of said baflle means to one of said pairs of chambers, means for transmitting said difference of air pressures from said conduit to the other of said pairs of chambers so that the forces on said diaphragms act in opposition to each other, a connection between said diaphragm and said one pair of contacts, and means responsive to the temperature of said engine for positioning the other pair of contacts.

10. Control apparatus for an internal combustion engine, comprisin a conduit for fuel flowing toward said engine, a pair of parallel metering restrictions in said conduit, 2, first valve, a selector valve movable between a first position wherein only one of said restrictions is open, a second position wherein both said restrictions are open and a third-position wherein said one restriction is open and the other restriction is connected in series with said first valve, first control means responsive to the temperature of said engine, second control means responsive to the rate of flow of cooling air past said engine, third con trol means responsive to the rate of combustion air flow to said engine, means including said first, second and third control means ior controlling the position of said ilrst valve, and means responsive to the rate of flow of combustion air to said engine for regulating the fuel pressure difierential across said restrictions.

11. Control apparatus for an internal combustion engine, comprising a conduit for fuel flowing toward said engine, a conduit for combustion air flowing to said engine, means associated with said conduits for regulating the fuel-air ratio, first control means responsive to the temperature of said engine, second control means responsive to the rate of flow of cooling air past said engine, third control means responsive to the rate of combustion air flow to said engine, and means including said flrst, second and third control means for operating said ratio regulating means.

12. Control apparatus for an internal combustion engine, comprisin a conduit for fuel flowing toward said engine, a conduit for combustion air flowing to said engine, means associated with said conduits for regulating the fuel-air, ratio, control means responsive to the rate of flow of cooling air past said engine, additional control means responsive to the rate of combustion air flow to said engine, and means including both said means for v operating said ratio regulating means.

13. Control apparatus for an internal combustion engine, comprising a conduit for fuel flowing toward said engine, a conduit for combustion air flowing to said engine, means associated with said conduits for regulating the fuel-air ratio, control means responsive to the temperature of said en v 12 gine, additional control means responsive to the rate of combustion air flow to said engine, and means including both said control means 10! operating said ratio regulating means.

14. Control apparatus for an internal combustion engine, comprising a conduit for fuel flowing toward said engine, a conduit for combustion air flowing to said engine, means associated with said conduits for regulating the fuel-air ratio, control means responsive to the temperature of said engine, additional control means responsive to the rate of flow of cooling air past said engine, means including both said control means for operating said ratio regulating means.

15. Control apparatus for an internal combustion engine, comprising cowl flaps for regulating the flow of cooling air over said engine, flrst control means responsive to the temperature of said engine, second control means responsive to the rate of flow of cooling air past said engine, third control means proportionally responsive to the rate of combustion air flow to said engine, and means including said flrst,'second and third control means for controlling the position oi said cowl flaps. i

16. Control apparatus for an internal combustion engine, comprising cowl flaps for regulating the flow of cooling air over said engine, control means responsive to the temperature of said engine, additional control means proportionally responsive to the rate of combustion air flow to said engine, and means including both said control means for controlling the position of said cowl flaps.

17. Control apparatus for an internal combustion engine, comprising cowl flaps for regulating the flow of cooling air over said engine, control means responsive to the rate of flow of cooling air past said engine, additional means proportionally responsive to the rate of combustion air flow to said engine, and means including both said control means for controlling the position of said cowl flaps.

18. Control apparatus for an internal combustion engine, comprising cowl flaps for regulating the flow of cooling air over said engine ignition timing control means, control means responsive to the temperature of said engine, and means including said temperature responsive means for simultaneously retarding the ignition timing and opening said flaps in response to an increase in engine temperature and advancing "said timing and closing said flaps in response to a decrease in engine temperature.

19. Control apparatus for an internal combustion engine, comprising ignition timing control means, means responsive to the rate of flow of cooling air past said engine, and means including said cooling air flow responsive means for retarding the ignition timing in response to a decrease in the rate of flow of cooling air past said engine, and advancing said timing in response to an increase in the rate of flow of cooling air past said engine.

20. Control apparatus for an internal combustion engine, comprising a throttle for controlling the flow of combustion air to said engine, stop means for limiting the opening movement 0! said throttle control, means responsive to the temperature of said engine and said combustion air flow, and means including said control means for increasingly limiting the opening movement of said throttle in response to an increase in engine temperature.

21. Control apparatus for an internal combustion engine, comprising a throttle for controlling the flow of combustion air to said engine, stop means for limiting the opening movement of said throttle, means responsive to the rate of flow of cooling air past said engine, and means includ ing said flow responsive means for increasingly limiting the opening movement of said throttle in response to a decrease in the rate of flow of cooling air past said engine.

22. Control apparatus for an internal combustion engine, comprising cowl flaps for regulating the flow of cooling air over said engine, control means proportionally responsive to the rate of combustion air flow to said engine, and means including said control means for positioning said cowl flaps.

23. Control apparatus for an internal combustion engine, comprising means for regulating the flow of cooling air over said engine, means for positioning said regulating means, and means for controlling said positioning means including mixture as the efiectiveness of the cooling meansis increased and to lean the mixture as the effectiveness of the cooling means is decreased, said controlling means including a device proportionally responsive to the rate of flow of combustion air to said engine to anticipate temperature changes due to changes in combustion air flow and thereby to prevent such changes by causing anticipatory movement of said controlling means.

25. Control apparatus for an internal combus- I tion engine, comprising cowl flaps for regulating the flow of cooling air over said engine, means responsive to detonation of said engine, and means including said detonation responsive means for positioning said cowl flaps to move said flaps in an opening direction upon detonation of said engine.

26. Control apparatus for an internal combustion engine, comprising means for cooling said engine, means for regulating the effectiveness of said cooling means, mixture control means for regulating the ratio of fuel to air supplied to said engine, and means for simultaneously controlling both said regulating means so as to enrich the mixture as the effectiveness of the cooling means is increased and to lean the mixture as the eflectiveness of the cooling means is decreased, said controlling means including means responsive to detonation of said engine.

27. A fuel control device for an internal combustion engine, comprising: a conduit for fuel flowing toward said engine, a first metering restriction in said conduit, metering means in said conduit in parallel with said first metering restriction, said metering means including a second metering restriction and a first valve in series with said second metering restriction; a selector valve and means for operation thereof between a first position wherein flow occurs only thru said first metering restriction, a second position wherein flow occurs directly through said first and second metering restrictions in parallel and by-passes said first valve, and a third position wherein flow occurs thru said first metering restriction and said metering means; means external of said device for gradually varying the posi tion of said first valve to control the flow thru said second metering restriction when said selector valve is in said third position, and means responsive to the rate of flow of combustion air to said engine for regulating the fuel pressure differential across said first metering restriction and said metering means.

28. A fuel control device for an internal combustion engine, comprising a main conduit for fuel flowing to said engine, first and second parallel branch conduits connected by a transverse passage, a selector valve located at the junction of one of said branch conduits and said transverse passage, first and second meterin restrictions in the respective branch conduits, a by-pass conduit extending from said main-conduit to said second branch conduit to a point therein between said second restriction and said selector valve, 9. second valve in said by-pass conduit, means for operating said selector valve between a first position wherein said first branch conduit is open and said second branch conduit and said transverse passage are closed, a second position wherein both said first and second branch conduits and said transverse passage are open, and a third position wherein said first and second branch conduits are open and said transverse passage is closed, means external of said device for gradually varying the position of said second valve to control the flow thru said second metering restriction when said selector valve is in said third position, and means responsive to the rate of flow of combustion air to said engine for regulating the fuel pressure differential between said ma conduit portions.

' LEIGHTON LEE, 11.

REFERENCES CITED The following references are of record in the file of this patent:

Twyman Dec. 25, 1945 

